This invention relates to disposable undergarments for absorption and containment of excretion and more particularly, to disposable undergarments such as diapers, training pants, incontinence pants or the like.
Japanese Patent Application Publication No. 1996-24291A describes a disposable pull-on diaper comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between these two sheets so as to configure a front waist region, a rear waist region and a crotch region extending between these two waist regions. The front and rear waist regions are connected to each other along transversely opposite side edge portions of these front and rear waist regions to define a waist-opening and a pair of leg-openings.
The known diaper is constructed as follows: A stretchable first elastic member is attached under tension to the diaper so as to extend in a circular arc from front ends of transversely opposite side edge portions of the diaper toward a longitudinally middle zone of the crotch region and a stretchable second elastic member is attached under tension to the diaper so as to extend in a circular arc from rear ends of the transversely opposite side edge portions of the diaper toward the longitudinally middle zone of the crotch region. The first and second elastic members respectively comprise both side portions extending in the vicinity of the front and rear ends of the transversely opposite side edge portions of the diaper and middle portions opposed to and spaced apart from each other in the longitudinal direction and extending across the longitudinally middle zone of the crotch region. A pair of stretchable third elastic members are attached under tension to the diaper along the transversely opposite side edge portions thereof so as to extend in the longitudinal direction between the respective middle portions of the first and second elastic members. The transversely opposite side edge portions define peripheral edge portions of respective leg-openings.
With this diaper put on the wearer, the thighs are fully and tightly surrounded by the both side portions of the first and second elastic members and the third elastic members although the first and second elastic members are spaced apart from each other in longitudinal direction in the crotch region, so there is no anxiety that leakage of excretion might occur in the crotch region.
However, desired contraction of the first and second elastic members in the middle portions thereof may be obstructed by the core having a stiffness higher than the top- and backsheets. Insufficient contraction of the middle portions makes it difficult to press a zone of the core against the wearer's skin since a good fit of the core to the wearer's skin relies on the contraction of the middle portions. Certainly it will be possible for the known diaper to press a middle zone of the core against the wearer's skin since the respective middle portions of the first and second elastic members extend across the longitudinally middle zone of the crotch region even if the contraction of the respective middle portions is insufficient. However, it is impossible for the known diaper to press the front and rear end zones of the core against the wearer's skin.